Articles containing glass-to-metal seals are well known to those skilled in the art; and the problems caused by stresses in such seals are also well known. Thus, for example, in an article published by Arun K. Varshneya in the Journal of the American Ceramic Society (Volume 63, Number 5-6, pages 311-315, 1980), it is disclosed (at page 311) that ". . . stresses in glass-to-metal seals develop as a result of the difference in thermal contraction of the two components from the point of sealing down to a lower temperature. Seals are likely to fail if tensile stresses reaching the breaking strength are generated in glass. Althought the science of stress calculations in glass-to-metal seals introduced by Hull and Burger . . . several years ago is still the most valuable guide, glass-to-metal sealing is still treated mostly as an `art.` One of the factors contributing to the empiricism is the relatively poor understanding of the rheological properties of glass."
Seals between metal and glass are especially important in articles in which hermeticity or thermal stability is required; such hermeticity and/or thermal stability is often required in electrical connectors.
Electrical connectors are widely sold by many different vendors. A "working temperature" and a "working pressure" is usually specified for the connector. Thus, by way of illustration, at page 20 of the Kemlon "Multipin Feedthru Electrical Connectors" catalog (published in 1989 by Kemlon Products & Development, 6310 Sidney, Houston, Tex.), a "KEMLON PMJ 304 S.S. BODY" connector is described. This connector has a working temperature of from minus 60 to 200 degrees centigrade and a working pressure of from 0 to 20,000 pounds per square inch. In this case, the low-temperature limit for the connector renders it unsuitable for many uses.
It is an object of this invention to provide a process for the preparation of articles containing glass-to-metal seals which will increase the working temperature range of such articles.
It is another object of this invention to provide a process for the preparation of articles containing glass-to-metal seals which will increase the working pressure range of such articles.